Treatment of rubber



Patented May 2, 19325 UNETEQ earner orr ca \FJILLIAM P. TER HORST, OF PACKANACK LAKE, NEW JERSEY, AS$IGNOR TO THE NAUGATUCK CHEMICAL COMPANY, OF NAUGA'I'UCK, CONNECTICUT, A CORPORATION OF CONNECTICUT TREATIVIENT OIE RUBBER No Drawing.

This invention relates to the treatment of rubber and similar materials, more particularly to a treatment of the same With an aldehyde derivative of the reaction. product of a lretone and an aromatic amine or amino compound. The invention also relates to the products of such treatment.

This case is a continuation-in-part of case Serial No. 411,665, filed December i, 1929.

An object of this invention is to provide materials having the property or" retarding the deterioration of rubber. Other objects Will be apparent from the following detailed description.

Examples of reaction products of ketones and aromatic amino compounds of which the aldehyde derivatives form the subject matter of this invention :aceton-e-aniline, acetone phenyl hydrazine, acetone p,p-diamino diphenyl methane, acetone-diphenylamine, ace tone diphenyl formamidine, mesityl oxideaniline, diacetone alcohol-aniline, acetone.- diphenyl betanaphthylamine, acetone-alpha naphthylamine, acetophenone-aniline, cycloheXanone-aniline, formaldehyde acetone condensation product-aniline, mesityl oxidepl'renyl beta naphthylamine, acetone-triphenyl melamine, acetone diortho tolyl guanidine, acetone-diphenyl guanidine, acetone p,p di (naphthylamino) diphenyl methane, acetone-ethyl aniline, tetramethyl diamido benzophenone-aniline, acetone-or tho-to'lyl biguanide, acetone-diphenyl diamino ethane, methyl ethyl kctone-p,p'-diamino diphenyl methane, ethylidene-aceto-nep,p'-diamino diphenyl methane, acetone mixture of beta naphthol and anil ne, acetone-mixture of phenol aniline, chloroacetone-aniline, acctone- {acetald-ehyde-aniline acid condensate).

Serial No. 564,980.

Illustrative of the invention is the treatment of rubber With such aldehyde derivahyde and acetone-aniline, reaction product 4 of formaldehyde and chloracetone-aniline.

Instead of the ketones mentioned above the following may be used: phorone, diethyl ketone, benzo phenone, aceto-phenone, dichlor acetone, aldol acetone, allylacetone, benzal acetone, diacetyl, acetyl-acetone, acetonylacetone, salicylaldehyde acetone, furfuralacetone. Instead of the aromatic amino compounds mentioned above there may be used mono-ohloroaniline, ortho-toluidine, meta toluidine, para-toluidine, Xylidines, alphanaphthylamine, beta naphthylamine, amino diphenyl, dinaphthylamines, asymmetric diphenyl hydrazine, diamino diphenyl sulphide, dianiino diphenyl po-lysulphides, diamino, dinaphthyl sulphides, p-amino benzyl-aniline, dinaphthyl diamino ethane, ditolyl diamino ethane, p-amino-pnaphthylamino diphenyl methane, p,p'-diamino diphenyl dimethyl methane, p,p-di- (naphthylamino) diphenyl dimethylmethane, symdiphenyl p-phenylene diamine, sym-dinaphthyl p-phenylene diamine, phenyl beta naphthyl guanidine, phenylo-tolyl guanidine, dio-tolyl biguanide, monophenyl biguanide,

iphenyl biguanide, diphenyl acetamidine.

The following are to be understood as illustrative embodiments of the invention and not limiting thereof:

Example .This type represents aldehyde reaction products of acetone-amines. Acetone-amines usually are liquids and the aldehyde derivatives usually are solid com pounds. As an example, an excess of 36% aqueous formaldehyde solution is added to the acetone-aniline reaction products, and enough hydrochloric acid is added to cause an acid reaction to litmus paper. The mixture is warmed to 50 C., at which temperature a. reaction suddenly starts. The temperature is kept at 70 C. during 30 minutes and the brittle product which is obtained on cooling is ground to a brown powder. The material is tested in the same manner as described above. The results are as follows:

Instead of formaldehyde other aldehydes may be used such as aldol, butyraldehyde, croton aldehyde, heptaldehyde.

Example Q.To 115.5 grams of the reaction product of acetone and diphenylamine are added 102.5 grams of 40% aqueous formaldehyde solution and two drops of concentrated hydrochloric acid. Heat is applied until a temperature of approximately C. is reached, at which point an exothermic reaction starts, causing the temperature to rise to approximately 70 C. When this first rather violent reaction is over the temperature is raised to approximately 80 C. by external application of heat and kept at 80 C. during 6 hours. The water formed during the condensation is then poured OE and the formaldehyde reaction product is washed, dried. and ground. The'product obtained is tested in carbon black stocks in which diphenyl guanidine is used as the accelerator. Two mixes were made up, one containing no antioxidant, called the blank, and another one containing my formaldehyde acetone-diphenylamine condensation product.

- 1.5 parts Green tensiles lbs/sq. in. Blank antioxidant Cure at 45# 4690 4423 Cure 75 at 45# 4497 4713 'Aged tensiles 168 hrs. in oxygen Cure 60 at 45#- 750 2175 Cure 75 at 45#- 837 2167 In truck inner tube in which the condensation product of butyraldehyde and aniline is used as the accelerator I obtain the following results:

+1 part antioxidant Green tensiies Blank Cure 5 at 60# Cure 10 at 601;

Aged 8 hrs. at 245 F. 100% elong. air

Cure 5 at 60# Cure 10 at 601'.

+ 1 part formaldchyde reaction product Green tensiles Blank Aged 168 hrs. in oxygen 1862 T00 poor to test.

A rubber tiling stock containing 06% of the formaldehyde derivative of acetone-diphenylamine reaction product is Vulcanized for 18 minutes at 60 lbs. steam pressure. A sample of the stock is then subjected to oxygen at 60 C. and at a pressure of 800 lbs. per sq. in. The sample fails after 240 hours whereas a similar stock containing no antioxidant fails in 24 hours. Samples of the cured stocks are also exposed to bright sunlight for two weeks. The sample containing the antioxidant is found to be discolored no more than the blank stock.

Ewample 35-In a second preparation of the acetone diphenlyamine-formaldehyde condensation product a much smaller amount of formaldehyde is used. To 100 grams of acetone-diphenylamine condensation product are added 20 grams aqueous formaldehyde solution 37% by weight and two drops concentrated hydrochloric acid. At 50 C. a reaction suddenly starts causing the temperature to rise to approximately 7 0 C. without application of external heat. The temperature is kept at 50 to 55 C. during 15 minutes.

The reaction mixture is then warmed to 105 C. in order to remove the water which was formed during the reaction. The procluct becomes solid on cooling and can be ground to a reddish brown powder. This material, which has a melting range of approximately to C. is tested in a carbon black stock in which diphenyl guanidine is used as the accelerator.

Stock contain- Green tensiles Blank ing 1 part antioxidant Cure at 45# 4712 4537 Cure 75 at 45# 4423 4417 Aged tensiles 168 hrs. in oxygen Cure 60 at 45# 1456 2736 Cure 75 at 45# 1495 3248 Green abrasions Cute 60' at 45# 132 120 Cure 75' at 45# 144 139 Abresions after 168 hrs. in oxygen Cure 60 at 45# 71 99 Cure 75 at 45# 71 95 Number of kilocycles to cause failure Green flex cracking 1 part antioxidant Blank In a truck inner tube in which a butyraldehyde-aniline condensation product is used as the accelerator I obtain the folowing results:

+ 1 part Green tensiles Blank antioxidant Cure 5 at 60# 3995 3110 Cure 10 at 60% 3355 3397 Aged 8 hrs. at 245 F. 100% elong. 70# air Cure 5 at 60# 444 Cure 10 at 60# 65 319 After the above ageing test the blank stock is very soft and sticky, whereas the stock containing the antioxidant is still comparatively strong and resilient.

Example 4.A third type of acetone diphenylamine formaldehyde condensation product is prepared simply from the acetonediphenylamine condensation product and formaldehyde, omitting the acid catalyst.

To 50 grams of the acetone-diphenylamine condensation product are added 30 grams 37% formaldehyde solution. The mass is heated to 80 C. at which temperature a reaction starts and proceeds rather violently. The temperature is kept at 90 during onehalf hour and the reaction mixture is allowed to stand during 16 hours. The water which formed during the reaction is then poured off and the reaction product is washed and air-dried. A light brown resin is obtained. This material possesses excellent antioxidant properties, as shown by the following results:

+ 1 part Green tensiles Blank antioxidant Cure 60 at 45# 4577 4508 Cure 75 at 45# 4600 4890 Aged 168 hrs. in oxygen Cure 60 at 45# 1168 2901 Cure 75 at 45# 1477 2972 The stock used in this test is a carbon black stock in which diphenyl guanidine is used as. the accelerator.

In a truck inner tube this type of acetonediphenylamine formaldehyde condensation product shows up very well.

Stock cont. 1 Green tensiles Blank part antioxidant Aged 8 hrs at 245 F. 100% along. air.

Example 5.Acetaldol-acetone diphenylamine condensation product. To 103.5 grams of acetone-diphenylamine condensation product and 40 grains acetaldol are added 2 drops of concentrated hydrochloric acid. When heat is applied a reaction starts at approximately 55 0., causing the temperature to rise to approximately C. The temperature is kept at to 90 C. during 6 hours. The excess aldol and the water formed during the reaction are removed by distillation. 114 parts of solid product are obtained This material is tested in a carbon black stock in which hexamcthylenete ramine and diphenyl guanidine are used as the accelerators. The stocks are subjected to ageing and abrasion tests, with the results indicated in the following table:

Stock cont. 1.5] Green tensiles Blank parts antioxident Cure 60' at 4310 3904 Cure 75 at 45# 4149 4630 Aged 168 hrs. in oxygen.

Cure at 45# 1598 3189 Cure at 45?; 2026 3092 Relative wearbefore ageing Cure 60' at 45# 144 142 Cure 75 at 45# 149 144 Relative wear after ageing 168 hrs. in oxygen bomb Cure 60 at 45# 87 119 Cure 75 at 45% 88 121 These results show the acetaldol-acetonediphenyl condensation product to be an excellent antioxidant.

Example 6.The butyraldehyde condensation product of acetone-diphenylamine reaction product is prepared as follows: 100 grams of butyraldehyde are added to 78 grams of acetone-diphenylamine reaction product containing 2 drops of concentrated hydrochloric acid, and heat is applied. At

60 C. a reaction starts. The temperature is kept during 6 hours at approximately 60 C. 47 parts of unreacted butyraldehyde are recovered by distillation. The reaction product is a black plastic mass. Yield, 104 x This material is tested in which hexamethylene tetramine and diphenyl guanidine are used as the accelerators. Tensile and abrasion tests were made before and after ageing, as above:

1 part Green tensile: Blank antioxidant Cure 60 at 45# 4177 4399 Cure 75 at 45# 4163 4377 Aged 168 hrs. in oxygen Cure 60 at 45# 1392 3150 Cure 75' at 45# 1360 3003 Relative wear before ageing Cure 60 at 45# 128 133 Cure 75 at 45# 133 135 Relative wear after ageing 168 hrs. in oxygen Cure 60 at 45# 80 112 Cure 75 at 45%; 84 114 This material when tested in a white sheeting stock in which penyl o-tolyl guanidine is used as the accelerator shows the following excellent antioxidant properties Instead of the aldehydes mentioned, other aldehydes may be used such as acetaldehyde,

paraldehyde, crotonaldehyde, heptaldehyde,

etc. Where the aldehyde has a 10w boiling point the reaction may be carried out under pressure. Instead of using a single aldehyde a mixture of aldehydes may be used. The

rubber also may be treated with a mixture of the antioxidants instead of a single antioxidant material. Also in preparing the ketone-amine compounds a mixture of ketones or a single ketone may be reacted with a single amino compound or with a mixture of amino compounds.

It is to be understood that a mixture of the reaction products may be used in rubber instead of a single reaction product. Also that a mixture of ketones or a single ketone may be reacted with a single amino compound or with a mixture of amino compounds to give products that may be used in rubber in the same manner. The chemicals disclosed may be used to improve the properties as mentioned herein of inner tubes, tires, thread, hose, dipped goods, 'mechanical goods, latex or articles made from latex, etc.

In the claims the term ketone is to be understood as meaning organic compounds containing one or more keto groups but containing no carboxylic acid or ester groups ral rubber, gutta percha, balata, synthetic rubber, or other rubber-like materials.

With the detailed description given above, will be obvious that modifications will sug-' gest themselves without departing from the principle of the invention, for example the product resulting from the reaction of a ketone and an aromatic amino compound may also be prepared by reacting the correspond ing thioketone or the corresponding ketone dihalide with the amino compound, and it is not desired to limit the invention otherwise than as set forth in the appended claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of a ketone and an aromatic amine.

2. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of an aliphatic lretone and an aromatic amine.

3. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of a ketone and an aromatic monoamine.

l. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of an aliphatic ketone and an aromatic monoamine.

5. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of acetone and an aromatic amine.

6. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of an aliphatic ketone and a primary aromatic amine.

7. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of an aliphatic lretone and a primary aromatic monoamine.

8. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of acetone and a primary aromatic amine.

9. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of acetone and an aromatic monoamine.

10. The method of treating rubber which comprises treating rubber with an aldehyde derivative of the reaction product of acetone and a primary aromatic monoamine.

11. The method of treating rubber which comprises treating rubber with a formaldehyde derivative of the reaction product of acetone and a primary aromatic amine.

12. The method of treating rubber which comprises treating rubber with a formaldehyde derivative of the reaction product of acetone and an aromatic monoamine.

13. The method of treating rubber which comprises treating rubber with a formaldehyde derivative of the reaction product of acetone and a primary aromatic monoamine.

14:. The method or" treating rubber which comprises treating rubber with a formaldehyde derivative of the reaction product of acetone and aniline.

15. Rubber derived from rubber containing an aldehyde derivative of the reaction product of a ketone and an aromatic amine.

16. Vulcanized rubber derived from rubber containing an aldehyde derivative of the reaction product of a ketone and an aromatic amine.

17. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction product of a ketone and an aromatic monoamine.

18. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction product of an aliphatic lretone and an aromatic monoamine.

19. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction product of acetone and an aromatic amine.

20. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the re action product of an aliphatic ketone and a primary aromatic amine.

21. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction product of an aliphatic ketone and a primary aromatic monoamine.

22. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction product of acetone and a primary aro matic amine.

23. A vulcanized rubber product containing rubber which has been vulcanized in the presence of an aldehyde derivative of the reaction of acetone and an aromatic monoamine.

24. A vulcanized rubber product containing rubber which has been vulcanized in the presence of a formaldehyde derivative of the reaction product of acetone and a primary aromatic amine.

25. A vulcanized rubber product containing rubber which has been vulcanized in the presence of a formaldehyde derivative of the reaction product of acetone and an aromatic monoamine.

26. A vulcanized rubber product containing rubber which has been vulcanized in the presence of a formaldehyde derivative of the reaction product of acetone and aniline.

27. A method of improving the properties of rubber compositions which comprises adding thereto the condensation product of formaldehyde and an aliphatic ketone-primary aromatic amine reaction product, and vulcanizing the rubber.

28. A method of improving the properties of rubber which comprises incorporating therewith the reaction product of an aliphatic aldehyde and a ketone-aromatic amine reac- 10 tion product.

29. A method of improving the properties of rubber which comprises incorporating therewith the reaction product of an aliphatic aldehyde and a dialkyl ketone-aromatic mono-amine reaction product.

30. A method of improving the properties of rubber which comprises incorporating therewith the reaction product of an aliphatic aldehyde and a dialkyl ketone-aromatic mono-amine reaction product.

Signed at Montclair, county of Essex, State of New Jersey, this 18th day of September, 1981.

WILLIAM P. Tm HORST. 

